integration by parts

[CellCoree]

hi, i would like help on a problem i am currently stuck on.

\int(e^x)/(1+e^(2x))dx <-- it's suppose to be \int (e^x)/(1+e^(2x))dx

using integration by parts, here's what i done:

u=e^x
du=e^x

dv=(1+e^(2x))
v = (need to use anti-differentiation, which i dont remeber....)

can i use integration by parts with this? this is cal 2.

[Crumbles]

hi, i would like help on a problem i am currently stuck on.

dv=(1+e^(2x))
v = (need to use anti-differentiation, which i dont remeber....)


Yes, v would be the integral of (1+e^(2x))

[Zurtex]

Erm, by-parts doesn't seem to make sense because actually:

u = e^x

dv = \frac{1}{1 + e^{2x}}

To me, it just looks like it is going to get nastier and nastier.

I would suggest using the substitution t = e^x because dt = e^xdx and if you look at the integral like this it becomes quite simple:

\int \frac{e^x dx}{1 + \left( e^x \right)^2}

[nrqed]

hi, i would like help on a problem i am currently stuck on.

\int(e^x)/(1+e^(2x))dx <-- it's suppose to be \int (e^x)/(1+e^(2x))dx

using integration by parts, here's what i done:

u=e^x
du=e^x

dv=(1+e^(2x))
v = (need to use anti-differentiation, which i dont remeber....)

can i use integration by parts with this? this is cal 2.

Hi,

I would not try an integration by parts. I would simply do a simple substitution u= e^x. Then you have the integral of du/(1+u^2) which is a basic one.

Pat